Incremental deployment and execution of a program on an embedded device

ABSTRACT

System and method for deploying and executing a program, e.g., a graphical program, on an embedded device. The program and a plurality of execution system components are stored on a host computer. The program is analyzed programmatically to determine a subset of the plurality of components required for execution of the program. The subset of components and the program are combined into a file while preserving execution order of the program. The file is transmitted to the device. The file is used to construct a combined program which includes executable code for the program and the subset of components. The device includes a minimal execution engine which executes the subset of components to execute the program. The file may be streamed to the device for streaming execution, where received portions of the subset of components needed for execution of received portions of the program are stored until no longer needed.

CONTINUATION AND PRIORITY DATA

This application is a divisional application of U.S. patent applicationSer. No. 10/283,548 titled “Deployment and Execution of a Program on anEmbedded Device,” filed Oct. 30, 2002 now U.S. Pat. No. 8,074,201, whoseinventors are Marius Ghercioiu, Ciprian Ceteras, Ioan Monoses, GratianI. Crisan, and Jeffrey L. Kodosky, which claims priority of U.S.Provisional Patent Application Ser. No. 60/394,895 titled “Deploymentand Execution of a Program on an Embedded Device”, filed Jul. 10, 2002,whose inventors were Marius Ghercioiu, Ciprian Ceteras, Ioan Monoses,Gratian I. Crisan, and Jeffrey L. Kodosky, and which are all herebyincorporated by reference in their entirety as though fully andcompletely set forth herein.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by any one of the patentdisclosure, as it appears in the Patent and Trademark Office patentfiles or records, but otherwise reserves all copyright rightswhatsoever.

FIELD OF THE INVENTION

The present invention relates to the field of programming, and moreparticularly to a system and method for executing a program, such as agraphical program, on an embedded device. A componentized programexecution system is described. A method is also presented for streamingexecution of a program by a minimal embedded execution system.

DESCRIPTION OF THE RELATED ART

Traditionally, high level text-based programming languages have beenused by programmers in writing application programs. Many different highlevel programming languages exist, including BASIC, C, Java, FORTRAN,Pascal, COBOL, ADA, APL, etc. Programs written in these high levellanguages are translated to the machine language level by translatorsknown as compilers or interpreters. The high level programming languagesin this level, as well as the assembly language level, are referred toherein as text-based programming environments.

Increasingly, computers are required to be used and programmed by thosewho are not highly trained in computer programming techniques. Whentraditional text-based programming environments are used, the user'sprogramming skills and ability to interact with the computer systemoften become a limiting factor in the achievement of optimal utilizationof the computer system.

There are numerous subtle complexities which a user must master beforehe can efficiently program a computer system in a text-basedenvironment. The task of programming a computer system to model orimplement a process often is further complicated by the fact that asequence of mathematical formulas, steps or other procedures customarilyused to conceptually model a process often does not closely correspondto the traditional text-based programming techniques used to program acomputer system to model such a process. In other words, the requirementthat a user program in a text-based programming environment places alevel of abstraction between the user's conceptualization of thesolution and the implementation of a method that accomplishes thissolution in a computer program. Thus, a user often must substantiallymaster different skills in order to both conceptualize a problem orprocess and then to program a computer to implement a solution to theproblem or process. Since a user often is not fully proficient intechniques for programming a computer system in a text-based environmentto implement his solution, the efficiency with which the computer systemcan be utilized often is reduced.

Examples of fields in which computer systems are employed to interactwith physical systems are the fields of instrumentation, processcontrol, industrial automation, and simulation. Computer measurement andcontrol of devices such as instruments or industrial automation hardwarehas become increasingly desirable in view of the increasing complexityand variety of instruments and devices available for use. However, dueto the wide variety of possible testing and control situations andenvironments, and also the wide array of instruments or devicesavailable, it is often necessary for a user to develop a custom programto control a desired system.

As discussed above, computer programs used to control such systemstraditionally had to be written in text-based programming languages suchas, for example, assembly language, C, FORTRAN, BASIC, etc. Traditionalusers of these systems, however, often were not highly trained inprogramming techniques and, in addition, text-based programminglanguages were not sufficiently intuitive to allow users to use theselanguages without training. Therefore, implementation of such systemsfrequently required the involvement of a programmer to write softwarefor control and analysis of instrumentation or industrial automationdata. Thus, development and maintenance of the software elements inthese systems often proved to be difficult.

U.S. Pat. Nos. 4,901,221; 4,914,568; 5,291,587; 5,301,301; and5,301,336; among others, to Kodosky et al disclose a graphical systemand method for modeling a process, i.e., a graphical programmingenvironment which enables a user to easily and intuitively model aprocess. The graphical programming environment disclosed in Kodosky etal can be considered a higher and more intuitive way in which tointeract with a computer. A graphically based programming environmentcan be represented at a level above text-based high level programminglanguages such as C, Basic, Java, etc.

The method disclosed in Kodosky et al allows a user to construct adiagram using a block diagram editor. The block diagram may include aplurality of interconnected icons such that the diagram createdgraphically displays a procedure or method for accomplishing a certainresult, such as manipulating one or more input variables and/orproducing one or more output variables. In response to the userconstructing a diagram or graphical program using the block diagrameditor, data structures and/or program instructions may be automaticallyconstructed which characterize an execution procedure that correspondsto the displayed procedure. The graphical program may be compiled orinterpreted by a computer.

Therefore, Kodosky et at teaches a graphical programming environmentwherein a user places or manipulates icons and interconnects or “wiresup” the icons in a block diagram using a block diagram editor to createa graphical “program.” A graphical program for performing aninstrumentation, measurement or automation function, such as measuring aUnit Under Test (UUT) or device, controlling or modeling instruments,controlling or measuring a system or process, or for modeling orsimulating devices, may be referred to as a virtual instrument (VI).Thus, a user can create a computer program solely by using a graphicallybased programming environment. This graphically based programmingenvironment may be used for creating virtual instrumentation systems,modeling processes, control, simulation, and numerical analysis, as wellas for any type of general programming.

A graphical program may have a graphical user interface. For example, increating a graphical program, a user may create a front panel or userinterface panel. The front panel may include various graphical userinterface elements or front panel objects, such as user interfacecontrols and/or indicators, that represent or display the respectiveinput and output that will be used by the graphical program or VI, andmay include other icons which represent devices being controlled. Thefront panel may be comprised in a single window of user interfaceelements, or may comprise a plurality of individual windows each havingone or more user interface elements, wherein the individual windows mayoptionally be tiled together. When the controls and indicators arecreated in the front panel, corresponding icons or terminals may beautomatically created in the block diagram by the block diagram editor.Alternatively, the user can place terminal icons in the block diagramwhich may cause the display of corresponding front panel objects in thefront panel, either at edit time or later at run time. As anotherexample, the front panel may comprise front panel objects, e.g., theGUI, embedded in the block diagram.

During creation of the block diagram portion of the graphical program,the user may select various function nodes or icons that accomplish hisdesired result and connect the function nodes together. For example, thefunction nodes may be connected in one or more of a data flow, controlflow, and/or execution flow format. The function nodes may also beconnected in a “signal flow” format, which is a subset of data flow. Thefunction nodes may be connected between the terminals of the varioususer interface elements, e.g., between the respective controls andindicators. Thus the user may create or assemble a graphical program,referred to as a block diagram, graphically representing the desiredprocess. The assembled graphical program may be represented in thememory of the computer system as data structures and/or programinstructions. The assembled graphical program, i.e., these datastructures, may then be compiled or interpreted to produce machinelanguage that accomplishes the desired method or process as shown in theblock diagram.

Input data to a graphical program may be received from any of varioussources, such as from a device, unit under test, a process beingmeasured or controlled, another computer program, or from a file. Also,a user may input data to a graphical program or virtual instrument usinga graphical user interface, e.g., a front panel as described above. Theinput data may propagate through the block diagram or graphical programand appear as changes on the output indicators. In an instrumentationapplication, the front panel can be analogized to the front panel of aninstrument. In an industrial automation application the front panel canbe analogized to the MMI (Man Machine Interface) of a device. The usermay adjust the controls on the front panel to affect the input and viewthe output on the respective indicators. Alternatively, the userinterface may be used merely to view the input and output, or just theoutput, and the input may not be interactively manipulable by the userduring program execution.

Thus, graphical programming has become a powerful tool available toprogrammers. Graphical programming environments such as the NationalInstruments LabVIEW product have become very popular. Tools such asLabVIEW have greatly increased the productivity of programmers, andincreasing numbers of programmers are using graphical programmingenvironments to develop their software applications. In particular,graphical programming tools are being used for test and measurement,data acquisition, process control, man machine interface (MMI),supervisory control and data acquisition (SCADA) applications,simulation, image processing/machine vision applications, and motioncontrol, among others.

In parallel with the development of the graphical programming model,embedded measurement and control systems have been developed for a widevariety of applications, such as automated manufacturing and remote datacollection, among others. However, in many prior art systems it is oftenthe case that the memory footprint of an application, e.g., a program,e.g., a graphical program, is too large to be stored and executed on anembedded device. This situation may be exacerbated by the fact that anexecution system and/or operating system required to execute theapplication may also have a relatively large footprint in the targetembedded device, thereby limiting further the applications which may berun on the device.

Therefore, improved systems and methods are desired for executingprograms on embedded devices.

SUMMARY OF THE INVENTION

One embodiment of the present invention comprises a system and methodfor deploying and executing a program, e.g., a graphical program, on anembedded device. The system may include a host computer system coupledto a target embedded device over a network or other transmission means.The program may be created on the computer system and transmitted to theembedded device for execution.

In one embodiment, the program that is created on the computer systemmay require use of an execution system to execute the program. Forexample, the program may require an operating system or similar softwareto execute. As another example, in one embodiment, the program is agraphical program and requires a graphical program execution system toexecute. Due to the small allowable footprint of the target device, inone embodiment, the program execution system is configured in such a wayso as to only transmit the minimum amount of the program executionsystem (e.g., a portion of a modular callback system) actually requiredby the program that is being executed. Thus, in one embodiment, theprogram execution system is partitioned into a (minimal) base executionsystem, and a plurality of components for enabling execution ofdifferent program functionality. The base portion of the programexecution system may only be capable of executing the very simplestcommands. This minimal system may comprise the smallest set of commandswhich allows the other components to be executed. The base portion ofthe program execution system may be stored on the target device, andonly the required components (as determined based on the program to beexecuted) may be transmitted to the target device, e.g., on an as-neededbasis.

In one embodiment, when the program is developed by the user, a softwareprogram executing on the computer may operate to analyze the program todetermine the functionality contained in the program. Once thefunctionality of the program has been identified, the program uses thefunctionality to determine which of the respective components of theprogram execution system are actually required by the program. In oneembodiment, the method determines the functionality of the program, anduses the functionality to index into a data structure or look-up tableto determine which program execution system components will be requiredto execute this program. When the program is then transmitted ordeployed to target device, the computer system may operate to onlyprovide the program execution system base portion (if the base portionis not already resident on the target device) and the respectivecomponents that are actually required to execute the program. Thus, asmaller amount of execution system code may be transmitted to the targetdevice. This allows a smaller footprint for one or more of the targetdevices and/or the sensor devices. In other words, the target device mayinclude a smaller processor and/or a smaller memory medium since a fullprogram execution system is not required to be transmitted.

In one embodiment, after the software program analyzes the program todetermine the functionality contained in the program, an executionsystem analysis program may determine which execution system componentsare required for execution of the program. A deployment program may thenassemble the required components of the execution system and theprogram, for example, by interspersing the required execution systemcomponents and the program together according to the order of executionof the program. These interspersed program execution system componentsand program may then be assembled into a file (e.g., a flatfile or“deployment file”), and respective portions of the file may betransmitted to the target device for execution. The file may optionallybe compressed prior to transmission.

In one embodiment, the flatfile may be received by the target device andused to construct a combined program including executable code from theprogram and executable code from the required execution system. Thiscombined program may then be executed by the embedded device. Thecombined program may also be stored in non-volatile memory of theembedded device for subsequent execution.

In one embodiment, successive portions of the file may be streamed tothe target device and/or sensor device for dynamic execution. In otherwords, the target device may execute the program as it is streamed tothe device. For example, the device may receive a first portion of thefile comprising a first portion of a program to be executed and a firstportion of the execution system components that are used for executingthis first portion of the program. After this first portion of theprogram has been executed along with the first portion of the executionsystem components, the first portion of the program may be flushed orremoved from the memory of the sensor device. In a similar manner, theexecution system components that are no longer required may be alsoremoved from the memory. However, execution system components that maybe required by other portions of the program to be executed may beretained in the memory for execution. In one embodiment, the deploymentprogram determines which execution system components may be required fora plurality of different portions of the program, and includes avariable or data structure or other indication with the execution systemcomponent to indicate that this component should not be flushedimmediately after it has been executed, but rather should be retained bythe target device for execution with another part of the program. Thus,the target device may maintain a type of “component buffer” fortemporarily storing execution system components that are required laterby other parts of the program (or by subsequent programs to beexecuted).

After the first portion of each of the program execution components andthe program has been executed, the computer system and/or target devicemay then provide a second portion of the program interspersed with thesecond portion of the execution system components. The second portion ofthe file may be provided by the computer system to the target device.Operation then proceeds as above. Thus, for example, the computer systemmay operate to provide respective portions of the deployment file to thetarget device for execution on an as needed basis, based on the memoryavailability or memory capacity of the target device. The target devicemay receive a portion of the program that it is supposed to executealong with the execution system components used by that portion of theprogram, execute the program under direction of the execution systemcomponents, and then receive further portions of the deployment file,and so forth. Thus, the computer system may essentially provide a streamof the program and its corresponding execution system components to thetarget device according to the order of execution of the program.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present invention can be obtained when thefollowing detailed description of the preferred embodiment is consideredin conjunction with the following drawings, in which:

FIGS. 1A and 1B illustrate embodiments of a system for execution of aprogram in a minimal embedded system;

FIG. 2 is a block diagram of the system of FIG. 1A, according to oneembodiment;

FIG. 3 is a block diagram of the computer system of FIGS. 1A, 1B, and 2,according to one embodiment;

FIG. 4A is a hardware layout of a minimal embedded system, according toone embodiment;

FIG. 4B illustrates the embedded target device of FIG. 4A, according toone embodiment;

FIG. 4C illustrates another example of an embedded target device,according to one embodiment;

FIG. 5 illustrates a minimal execution system, according to oneembodiment;

FIG. 6 flowcharts a method for creating the minimal execution system ofFIG. 5, according to one embodiment;

FIG. 7 graphically illustrates componentization of a callback system,according to one embodiment;

FIG. 8 flowcharts one embodiment of a method for componentizing acallback system to generate a modular callback system;

FIG. 9 illustrates a process of generating a flatfile from a program andthe modular callback system, according to one embodiment;

FIG. 10 flowcharts one embodiment of a method for generating the programflatfile;

FIGS. 11A-11C illustrate the structure and deployment of the programflatfile, according to one embodiment;

FIG. 12 flowcharts one embodiment of a method for deploying andexecuting a program on an embedded device; and

FIGS. 13-46 are screen shots of graphical program source code which mayimplement one embodiment of the invention.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and are herein described in detail. It should beunderstood, however, that the drawings and detailed description theretoare not intended to limit the invention to the particular formdisclosed, but on the contrary, the intention is to cover allmodifications, equivalents and alternatives falling within the spiritand scope of the present invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Incorporation byReference

The following references are hereby incorporated by reference in theirentirety as though fully and completely set forth herein:

-   U.S. Provisional Patent Application Ser. No. 60/394,895 titled    “Deployment and Execution of a Program on an Embedded Device”, filed    Jul. 10, 2002.-   U.S. Pat. No. 4,914,568 titled “Graphical System for Modeling a    Process and Associated Method,” issued on Apr. 3, 1990.-   U.S. Pat. No. 5,481,741 titled “Method and Apparatus for Providing    Attribute Nodes in a Graphical Data Flow Environment”.-   U.S. Pat. No. 6,173,438 titled “Embedded Graphical Programming    System” filed Aug. 18, 1997.-   U.S. Pat. No. 6,219,628 titled “System and Method for Configuring an    Instrument to Perform Measurement Functions Utilizing Conversion of    Graphical Programs into Hardware Implementations,” filed Aug. 18,    1997.-   U.S. patent application Ser. No. 09/617,600 titled “Graphical    Programming System with Distributed Block Diagram Execution and    Front Panel Display,” filed Jun. 13, 2000.-   U.S. patent application Ser. No. 09/518,492 titled “System and    Method for Programmatically Creating a Graphical Program,” filed    Mar. 3, 2000.-   U.S. patent application Ser. No. 09/745,023 titled “System and    Method for Programmatically Generating a Graphical Program in    Response to Program Information,” filed Dec. 20, 2000.-   The LabVIEW graphical programming manuals, including the “G    Programming Reference Manual”, available from National Instruments    Corporation, are also hereby incorporated by reference in their    entirety.    FIGS. 1A and 1B—Embedded Systems

FIGS. 1A and 1B illustrate embodiments of an embedded system forexecuting programs. As shown in FIG. 1A, the system may include acomputer system 102 coupled through a network 104 (or other transmissionmedium) to an embedded device 110, also referred to as a target device110. In other embodiments, such as illustrated in FIG. 1B, the computersystem 102 may be coupled to the target device 110 via an intermediatehub 108, which may communicate with the computer system 102 over thenetwork 102, and which may communicate with the target device 110 viawireless means.

The computer system 102 may be any of various types of computer systems.Computer system 102 may include a processor, a memory medium, as well asother components as may typically be found in a computer system. Thememory medium of the computer system may store a program developmentenvironment for creating programs. The computer system 102 is describedin more detail below with reference to FIG. 3. As used herein, the termprogram is intended to include text-based or graphical instructionswhich are executable, compilable, and/or interpretable by a processor orprogrammable hardware element (such as a Field Programmable Gate Array(FPGA)) to perform a specified function or functions.

In one embodiment, the program development environment is a graphicalprogram development environment for creating graphical programs. Anexemplary graphical program development environment is the LabVIEWdevelopment environment offered by National Instruments Corporation. Auser may create a program on a computer system, and computer system 102may provide the program to target embedded device 110, optionally viahub device 108.

Target device 110 may include a processor and memory medium forexecuting programs, such as graphical programs. In one embodiment, thetarget device 110 executes programs, e.g., graphical programs, receivedfrom the computer system over the network 104. In another embodiment,the computer system 102 sends the program to the hub device 108 over thenetwork 104, and the hub device 108 operates to deploy the programs tothe target device 110 in a wireless fashion, and the program executes ontarget device 110. It should be noted that in various embodiments, thetarget device 110 may be implemented in different devices, such as, forexample, a device with an ARM processor, as described below, a PXIchassis which includes an embedded device card, or any other processorbased device suitable for embedded systems. One exemplary target device110 is a smart sensor (e.g., a smart camera).

In one embodiment, the target device 110 may include a programmablehardware element, such as an FPGA. The target device 110 may be operableto receive a hardware configuration file, e.g., a netlist, which encodesa desired functionality, and to deploy the hardware configuration fileto the FPGA, thereby configuring the FPGA to perform the desiredfunctionality.

Target device 110 may be connected to computer system 102 by a network104 as shown. The network may be comprised of any of the various typesof networks including local area networks (LAN), wide area networks(WAN), etc. One example of a wide area network is the Internet. Targetdevice 110 may also connect to computer system 102 through othercommunication mediums, such as a serial bus, e.g., USB or IEEE 1394, aparallel bus, or through wireless means. The wireless communicationmechanism may comprise any of various types of wireless transmission,including Blue Tooth, IEEE 802.11 (wireless Ethernet), RF communication,and other types of wireless communications, such as, for example,communication via satellite, and cell towers, such as used for cellulartelephone communication, among others. In various embodiments, thetarget device 110 may include or may be coupled to one or more sensorsor actuators. For example, the target device may include a radio and maybe coupled to a sensor via wireless means. In one embodiment, one ormore of the sensors coupled to the target device 110 may be smartsensors, i.e., may include a processor and memory (and/or a programmablehardware element, such as an FPGA), and therefore may be operable toexecute program code and/or receive commands from the target device 110as a result of execution of the program code.

Embedded Devices

As mentioned above, in various embodiments of the present invention, anembedded device 110 may be coupled to the host computer 102. As usedherein, the term “embedded device” refers to a small platform whichincludes dedicated hardware, and which includes a processor and memory(or FPGA) on which may be installed dedicated programs or software. Anembedded device is typically designed to perform a defined task verywell. In particular, an embedded device is typically not a device withgeneral capabilities, such as a PC or PXI controller, for example,loaded with one or several plug-in boards, running a Microsoft OS withgenerous amounts of memory, system files, utilities, etc, that can beused as a measurement system, or as an office computer, or as a Webbrowser, etc. An example of an embedded system is an Internet remotecamera, with dedicated hardware and software that implements thefollowing tasks:

-   -   it acquires images from the optical device,    -   it compresses these images as GIF or JPEG files, or perhaps as        MPEG streams, and    -   it sends the images to a host computer upon request, using        TCP/IP, HTTP, or multimedia streams.

Other examples of embedded devices include a measurement device with aspecific type of measurement hardware and/or software for taking certainmeasurements, a control measurement device with a specific type ofhardware and/or software for performing certain control operations, etc.

The end user does not care about how these tasks are implemented, butonly wants a device that sends real-time images over the Internet.Embedded systems are often used as building blocks for more complicatedapplications. Thus, an embedded device generally includes both hardwareand software. Additionally, embedded devices are generally built arounda specialized hardware component, which is the “reason to exist” forthese devices (like the camera in the above example). Other typicalcomponents include: a processor, such as an ARM processor, RAM and ROMmemory, a storage medium, a display, one or more communication devices,and power and over-voltage protection components. Generally, flashmemory is used for data storage in addition to RAM.

FIG. 2—Block Diagram of the Data Acquisition System

FIG. 2 is a block diagram of the system of FIG. 1A, according to oneembodiment. In the embodiment shown in FIG. 2, the computer system 102includes a program development environment 201, e.g., a graphicalprogram development environment, which facilitates development ofprograms, e.g., graphical programs, for implementing desired functionsor operations, as well as a program execution system 203, also referredto as the execution system 203. The execution system 203 may be operableto execute programs developed with the program development environment201 (or other program development environments).

As used herein, the term “execution system” may include at least onesoftware program that is designed to execute a certain class ofprograms. For example, LabVIEW programs utilize an execution system (aLabVIEW graphical program execution engine) that executes in a system inorder to execute LabVIEW graphical programs.

As will be described in more detail below, the execution system 203 mayinclude a componentized or modular architecture, e.g., a componentizedcallback system, stored on the computer system for partial transfer toan external device, e.g., the target device 110. In other words, thefunctions of the execution system 203 may be organized into modularcomponents which may be operable to be transferred entirely or in partto the target embedded device 110 to facilitate execution of programs onthe target embedded device 110. In many of the embodiments describedherein, the systems and methods are described in terms of graphicalprograms, although it should be noted that the invention is broadlyapplicable to other types of programs as well, e.g., text-basedprograms, etc., and is not intended to be limited to graphical programs.

As FIG. 2 also shows, the computer system 102 may also store one or moreprograms 202 (e.g., graphical programs) which are executable via theexecution system 203 (or portions thereof) to perform specifiedfunctions or operations, as desired. In the embodiment shown, thegraphical program 202 may be stored for transferal to the targetembedded device 110 for execution. As will also be described in moredetail below, various components of the execution system 203 may becombined with respective portions of the graphical program 201 fortransferal to the target device 110 for execution. The computer system102 may also include a network interface 204 for communicating over thenetwork 104 with devices on the network 104. For example, the networkinterface 204 may be an Ethernet interface for communicating over theInternet 104. Further details of the computer system 102 are providedbelow with reference to FIG. 3.

In an alternate embodiment, the graphical program 201 may be providedfrom a first computer, and components of the execution system 203necessary for execution of this graphical program may be provided from asecond different computer system.

In the embodiment of FIG. 2, the target device 110 includes an operatingsystem 210, e.g., a real-time operating system (OS), for managingprogram execution, managing device resources, and communications inembedded devices, as is well known in the art. Examples of real-timeoperating systems 210 include, but are not limited to, Linux, NetBSD,vxWorks, eCos, and Windows CE. Due to size and performance issues, theeCos real-time operating system may be particularly suitable for use inthe embedded target device 110, although other real-time operatingsystems are also contemplated. The target device 110 may also include atarget execution system (or “minimal execution system”) 205, whichpreferably is a minimal embedded graphical program execution system 205,and which may include a subset of the execution system 203 stored on thecomputer system 102, mentioned above. The minimal execution system 205may be optimized to minimize the memory footprint on the target device110, as described below with reference to FIG. 5. In one embodiment, theminimal execution system 205 may comprise an execution system virtualmachine. The minimal execution system 205 may facilitate execution ofgraphical program(s) 202 by the target device 110. More specifically,the graphical program 202 stored on the computer system 102 may becombined with one or more components of the componentized callbacksystem of execution system 203 to generate a flatfile 207 which may betransferred to the target embedded device 110. The flatfile 207 may bedirectly executable by the target device 110. Alternatively, theflatfile 207 may be used in constructing a combined program 202A on thetarget device 110, wherein the combined program 202A may be executed onthe target device 110. The flatfile 207 and the combined program 202Aare described in detail below. The target embedded device 110 may alsoinclude software for performing various functions related to the presentinvention, such as a program linker/loader, which in various embodimentsmay be comprised in the real-time OS, the minimal execution system 205,or may be stored and executed as a separate program. The structure andprocessing of the flatfile 207 according to one embodiment are describedin detail below with reference to FIGS. 11A-11C.

FIG. 3—Computer System Block Diagram

FIG. 3 is a block diagram for a computer system 102 suitable forimplementing various embodiments of the present invention. Morespecifically, the computer system 102 may be operable to store anddownload to the target device 110 a graphical program that is configuredto perform a specified function. Embodiments of a method fortransmitting and executing the graphical program are described below.The computer system 102 may be any type of computer system, including apersonal computer system, mainframe computer system, workstation,network appliance, Internet appliance, personal digital assistant (PDA),television system or other device. In general, the term “computersystem” can be broadly defined to encompass any device having at leastone processor that executes instructions from a memory medium. Thecomputer may include at least one central processing unit or CPU 160which is coupled to a processor or host bus 162. The CPU 160 may be anyof various types, including an x86 processor, e.g., a Pentium class, aPowerPC processor, a CPU from the SPARC family of RISC processors, aswell as others.

The computer system 102 may include a memory medium(s) 166 on which oneor more computer programs or software components according to oneembodiment of the present invention may be stored. For example, thememory medium may store a graphical program execution system, as well asone or more graphical programs, as described above. Also, the memorymedium may store a graphical programming development environmentapplication used to create and/or execute such graphical programs. Thememory medium may also store operating system software, as well as othersoftware for operation of the computer system.

The term “memory medium” is intended to include an installation medium,e.g., a CD-ROM, floppy disks 104, or tape device; a computer systemmemory or random access memory such as DRAM, SRAM, EDO RAM, Rambus RAM,etc.; or a non-volatile memory such as a magnetic media, e.g., a harddrive, or optical storage. The memory medium may comprise other types ofmemory as well, or combinations thereof. In addition, the memory mediummay be located in a first computer in which the programs are executed,or may be located in a second different computer which connects to thefirst computer over a network, such as the Internet. In the latterinstance, the second computer may provide program instructions to thefirst computer for execution.

Various embodiments further include receiving or storing instructionsand/or data implemented in accordance with the foregoing descriptionupon a carrier medium. Suitable carrier media include a memory medium asdescribed above, as well as signals such as electrical, electromagnetic,or digital signals, conveyed via a communication medium such as networksand/or a wireless link.

As FIG. 3 shows, the memory medium 166 may be coupled to the host bus162 by means of memory controller 164. The host bus 162 may be coupledto an expansion or input/output bus 170 by means of a bus controller 168or bus bridge logic. The expansion bus 170 may be the PCI (PeripheralComponent Interconnect) expansion bus, although other bus types can beused. The expansion bus 170 includes slots for various devices, such asa network interface card 114, a video display subsystem 180, and harddrive 1102 coupled to the expansion bus 170.

In the present application, the term “graphical program” or “blockdiagram” is intended to include a program comprising graphical code,e.g., two or more interconnected nodes or icons, wherein theinterconnected nodes or icons may visually indicate the functionality ofthe program. The nodes may be connected in one or more of a data flow,control flow, and/or execution flow format. The nodes may also beconnected in a “signal flow” format, which is a subset of data flow.Thus the terms “graphical program” or “block diagram” are each intendedto include a program comprising a plurality of interconnected nodes oricons which visually indicate the functionality of the program.

A graphical program may also comprise a user interface or front panel.The user interface portion may be contained in the block diagram or maybe contained in one or more separate panels or windows. The userinterface of a graphical program may include various graphical userinterface elements or front panel objects, such as user interfacecontrols and/or indicators, that represent or display the respectiveinput and/or output that will be used by the graphical program or VI,and may include other icons which represent devices being controlled.The user interface or front panel may be comprised in a single window ofuser interface elements, or may comprise a plurality of individualwindows each having one or more user interface elements, wherein theindividual windows may optionally be tiled together. As another example,the user interface or front panel may comprise user interface or frontpanel objects, e.g., the GUI, embedded in the block diagram. The userinterface of a graphical program may display only output, only input, orboth input and output. Further, in some embodiments the user interfaceoperates as a front panel, wherein the user can interactively control ormanipulate the input being provided to the graphical program duringprogram execution and can view resulting output.

Examples of graphical programming development environments that may beused to create graphical programs include LabVIEW, DasyLab, and DiaDemfrom National Instruments, VEE from Agilent, WiT from Coreco, VisionProgram Manager from PPT Vision, SoftWIRE from Measurement Computing,Simulink from the MathWorks, Sanscript from Northwoods Software, Khorosfrom Khoral Research, SnapMaster from HEM Data, VisSim from VisualSolutions, ObjectBench by SES (Scientific and Engineering Software), andVisiDAQ from Advantech, among others. In the preferred embodiment, thesystem uses the LabVIEW graphical programming system available fromNational Instruments.

FIG. 4A—Embedded Device Hardware Configuration

FIG. 4A illustrates a hardware configuration of one embodiment of atarget embedded device, as shown in FIGS. 1A, 1B, and 2. It should benoted that the embodiment shown is intended to be exemplary only, and isnot meant to limit the target embedded device to any particulararchitecture, components, size, or form.

In the embodiment shown in FIG. 4, the target embedded device 110 mayinclude an I/O connector 402 coupled to a 4-channel multiplexer (MUX)402, connected to a 4-channel 16-bit ADC 408, a temperature sensor 404,a micro-controller with internal flash program memory and data SRAM 406,and Ethernet port 414. In this embodiment, power is provided by a 5 voltDC power supply 412. The processor 406, an ATMEL ARM Thumb AT91FR4081,has a high-performance 32-bit RISC architecture with high-density 16-bitinstruction set and very low power consumption. By combining themicro-controller, featuring 136 Kbytes on on-chip SRAM and a wide rangeof peripheral functions, with 8 Mbits of Flash memory in a singlecompact 120-ball BGA package, the Atmel AT91FR4081 406 provides apowerful, flexible, and cost-effective solution to the minimal embeddedcontrol application. Significant board size reduction is also noted as abenefit.

FIG. 4B—Embedded Device Hardware

FIG. 4B illustrates the embedded hardware of FIG. 4A, according to oneembodiment. As FIG. 4B shows, the hardware components included in thetarget embedded device 110 facilitate an extremely compact form factor.

FIG. 4C—Another Example of Embedded Device Hardware

FIG. 4C illustrates another embodiment of the embedded target device110, according to one embodiment. As FIG. 4C shows, in this embodiment,substantially all of the functionality included on the board is modular.For example, different I/O boards 420 may be selected and plugged-independing on the type of sensors required by the application. In thisembodiment, components which may be provided by additional modules(e.g., cards) have been remove, such as the temperature sensor 404 andthe ADC 408. In this embodiment, a micro-controller with internal 1 MBof flash program memory and 128 kb of data SRAM is connected via SPI(serial peripheral interface) to an analog small form-factor DAQ slot,and is further connected via a digital bus to a digital smallform-factor DAQ slot. This embodiment may be particularly suited forsmart sensing, computing, and control, due to the design emphasis onmodularity.

In all of the embodiments shown above, it is noted that only necessaryacquisition and processing code is packaged and downloaded onto theembedded device (using the flatfile). An approach for generating thisminimized code is described below with reference to FIGS. 5-9.

FIG. 5—Minimal Execution System

FIG. 5 illustrates the determination of a reduced or minimal set offunctionality needed to execute graphical programs. This minimal set isincluded in the minimal graphical program execution system 205 which isinstalled on the target embedded device 110, and which operates toexecute the (combined) graphical program (via the graphical programflatfile 207) on the target device 110. The term “minimal” is not used

FIG. 5 compares a minimal graphical program execution system 205 with anun-optimized (for small memory footprint) graphical program executionsystem 500. As FIG. 5 shows, the graphical program execution system 500may include an execution engine 502, a network manager 504, a callbacksystem 506, and other components 508. In a typical graphical programexecution system, there may be as many as (or more than) 30 components,and so the execution system may be quite large. Such a system mayoperate under a real-time OS, such as Linux, which has a size of roughly1.5 MB (mega-bytes). In this typical graphical program execution system,the amount of available memory may be quite large, and hence there istypically no need to reduce the size of the graphical program executionsystem.

In contrast, the target device may have a limited memory size, e.g., dueto power and/or cost constraints. In addition, a real-time OS 210 forthe embedded target device 110, such as eCos, may only be 50 KB in size,and so the execution engine is preferably scaled down accordingly to runon the embedded device 110 under the embedded real-time OS 210. This maybe accomplished by modifying or removing various sub-systems of theexecution system 500 that are not required for basic execution. Forexample, in one embodiment, the minimal execution system may includeonly a portion of the execution engine 502A, as shown, along with asubstantially modified network manager 504A. Other components may beomitted altogether. Thus, a minimal execution system 205 may begenerated with greatly reduced size, and somewhat reduced functionalityin order to fit on the embedded target device 110. The minimal executionsystem 205 may be the absolute smallest executable execution system 205,or simply a reduced version of the execution system 205 including a coreset of functionality.

As FIG. 5 also shows, in one embodiment, the callback system 506 may beomitted from the minimal execution system 205. Instead, the callbacksystem 506 may be replaced with a componentized or modular callbacksystem 206 which is stored on the host computer 102, and which may betransferred in part to the target device 110 depending on the needs ofthe particular graphical program. The componentization of the callbacksystem 506 is described below with reference to FIGS. 7 and 8.

FIG. 6—Method of Creating a Minimal Graphical Program Execution System

FIG. 6 flowcharts one embodiment of a method for creating a minimalgraphical program execution system, as described above with reference toFIG. 5. It is noted that in various embodiments, one or more of thesteps may be performed in a different order than shown, or may beomitted. Additional steps may also be performed as desired.

As FIG. 6 shows, in 602, the original graphical program execution system500, as described above in FIG. 5, may be analyzed and pared down to theminimum set of functionality required to execute an extremely simple VI,e.g., a two integer addition (1+1=2) or a set of simple VIs. In oneembodiment, this may include removing such subsystems as the web server,XML support, and the callback table. Then, all the functions that arenamed in the callback table (which are candidates for modularization andaren't required for the simple VIs) may be removed. Finally, a codecoverage test may be perform in order to find and remove the functionsthat were not called in executing the simple VI (or a set of simpleVIs). The resulting code comprises an initial version of the minimalexecution engine 205.

Then, in 604, the resulting code may be profiled to determined how muchcode memory and RAM memory it occupies, and to decide which of theremaining subsystems are too large and should be redesigned. Forexample, for the system described above based on the ARM processor, atarget memory footprint of 50K may require trimming those subsystemsthat are required and are too large in the original execution system. Asan example, the network manager and type system may need to beredesigned if they were implemented with too large buffers in theoriginal execution system.

Finally, in 606, if the original execution system VI linker does not fitthe design, special subsystems, e.g., VI2OBJ and FLATFILE systems, maybe built. In other words, components for converting VIs to object files(VI2OBJ) and for generating the modules for the flatfile (FLATFILE) maybe created. Further information regarding the generation of object filesfor VIs is provided below in the section titled VI Object Files.

Thus, in one embodiment, a minimal execution engine 205 may beconstructed by removing all but the minimum functionality required toexecute a VI (graphical program), including most or all of the callbacksystem 506, leaving the portion of the execution engine 502A and amodified network manager 504A, as described above. Such a minimalexecution system 205 may then be suitable for loading and executing onan embedded device 110. In one embodiment, the minimal execution systemmay comprise an execution system virtual machine.

It should be noted that the process described above with reference toFIGS. 5 and 6 may also be applied to operating systems, such as areal-time operating system (OS). In other words, an operating system maybe optimized, modularized, and/or modified to minimize the footprint onthe target device 110. For example, the operating system may be analyzedto determine a minimal kernel or core functionality necessary for the OSto operate. For example, in one embodiment, the minimum functionalitymay include a simple Basic I/O Service (BIOS) and/or a minimumcommunication service, such as a TCP/IP service, as is well known in theart. As another example, the minimum functionality may include a simpledownloading capability or functionality, e.g., a download protocol.Thus, in various embodiments, the minimum functionality may include oneor more of: a simple BIOS, a minimum network communications protocol(e.g., TCP/IP), and/or a minimum download capability. In anotherembodiment, the minimum functionality may include a hardware and/orsoftware checking capability. Other functions or services of the OS,such as I/O, memory management (e.g., trash collection, etc.) etc., maybe modularized or partitioned such that subsets of the functions orservices needed for a particular application or device may be determinedand transmitted as needed. Thus, in one embodiment, a distributed,“on-demand” OS may be created which includes the kernel (or minimumfunctionality), and one or more transferable OS modules which provideadditional OS functionality in a modular fashion. Thus, the minimumfunctionality may facilitate subsequent downloading of support librariesand executing kernel components, i.e., in one embodiment, the minimumfunctionality may be just enough to allow the device to download furtherbasic OS capabilities, including portions of the kernel and/or the BIOS.In another embodiment, these further basic OS capabilities may beincluded with an application, as described in detail below.

Thus, in one embodiment, the OS kernel or core functionality may resideon the target device 110, and may be executable to perform basic OSfunctionality on the device. Then, based on analysis of the application(e.g., a graphical program and/or the desired task, and/or the targetdevice), one or more OS modules may be selected to provide particularneeded services. These OS modules may then be transmitted to the targetdevice 110 and installed (e.g., by the kernel or other loader program)to augment the basic OS functionality provided by the kernel, afterwhich the OS (now extended) may be operable to provide the additional OSservices or functionality.

In various embodiments, the one or more OS modules may be transmittedalone, or along with or as part of the target application. For example,in one embodiment, the one or more OS modules may be included in aflatfile 207 (or other structure or file) along with modules from thegraphical program, and possibly also with modules (components) of themodular callback system 206.

FIG. 7—Componentization of the Graphical Program Callback System

FIG. 7 illustrates the process of componentizing a monolithic graphicalprogram callback system 506 to generate the modular graphical programcallback system 206, according to one embodiment. It should be notedthat the callback system of FIG. 7 is a highly simplified model which isintended only to illustrate the process, and is not meant to representan actual callback system.

As FIG. 7 shows, the monolithic graphical program callback system 506includes a plurality of functions A-K (702-722) with varyingdependencies. In many prior systems, the functions are arbitrarilystored in many different files, which generally accumulate over time asthe function library is developed. Thus, locating functions for linkingand execution may be difficult and expensive, since functionaldependencies may span numerous files in a substantially haphazardmanner. As a result, when linking files for a particular application(graphical program), many unnecessary functions may be included due tothe fact that they happened to be located in the same files as needfunctions, thus, the resulting memory footprint of the executable may beunnecessarily large.

The approach used herein to modularize the functions is to analyze thefunctional dependencies of the functions, and to group functions whichoperate relatively independently from other functions as a module. Forexample, as FIG. 7 shows, function A 702 calls function B 704 andfunction C 706. Function B 704 calls function D 708, and function C 706calls function E. Thus, function A 702 has a dependency on function B704, function C 706, function D 708, and function E 710.

Similarly, function F 712 depends on function G 714, function H 716,function I 718 and function J 720, as well as function C 706 (and itschild function E 710). Note that function C 706 (and its child functionE 710) is called by both function A 702 and function F 712. Thisdependency overlap may be resolved by grouping any function (with itschildren) which is called by multiple other functions as a separatemodule. Thus, a first module, module 1 762, may include function A 702,function B 704, and function D 708, as indicated in the modular callbacksystem 203. Module 2 764 includes function C 706 and function D 708, asshown. Module 3 766 includes function F 712, function G 714, function H716, function I 718 and function J 720. Note that module 1 762 andmodule 3 766 both depend on module 2 764 (since both function A 702 andfunction F 712 call function C 706). This module dependency relationshipmay be maintained in a module dependency table 730 or its equivalent. AsFIG. 7 also shows, function K is independent of any other functions, andso has its own module, module 4 768.

In one embodiment, each module may be stored in a separate file, greatlyeasing the task of a dependency checker when selecting modules/filesneeded by the graphical program 202, i.e., for inclusion in the flatfile207. A method for performing this componentization is described belowwith reference to FIG. 8.

FIG. 8—Method for Componentizing a Graphical Program Execution System

FIG. 8 flowcharts one embodiment of a method for componentizing agraphical program execution system, such as, for example, LabVIEW RT.More specifically, as described above with reference to FIG. 7, themethod componentizes or modularizes a set of functions (e.g., thefunction library) of the execution system, also referred to as thecallback system of the execution system, by grouping functions in filesor modules based on dependencies.

For example, in one embodiment, the original source code of the callbacksystem includes a set of files that each contains functions that maycall other functions, that may call other functions, etc., that belongto other files. If a function's dependencies extend into several files,it may be difficult or impossible for a dependency checker to identifyand retrieve the function. To facilitate a dependency checker being ableto select from the callback system source code only those functions thatare needed by a particular application, an attempt may be made to placeeach function with it's dependencies into a single file. This “complete”function file (e.g., with *.cpp extension) may comprise a module. Thus,componentization of the graphical program execution engine may includethe creation of modules, or *.cpp files, that completely (or almostcompletely) describe a function.

The following describes one approach for performing thiscomponentization, using functions A, B, and C for illustrative purposes.It is noted that in various embodiments, one or more of the steps may beperformed in a different order than shown, or may be omitted. Additionalsteps may also be performed as desired.

As FIG. 8 shows, each function may be analyzed with respect to itsfunctional dependencies to determine whether to place the function in aseparate module or in a module with another function. For example:

In 802, a next function, e.g., function A, may be selected, such as fromthe callback system of the graphical program execution engine. Then, adetermination may be made as to whether function A has dependencies,i.e., calls a function B, as indicated in 804. If function A has nodependencies, i.e., does not call function B, then a module or file maybe created for function A, as shown in 808.

If in 804 function A does call function B, then in 806 a determinationmay be made as to whether function B is also called by another function,e.g., function C. In other words, the method may check to see if anyother function has a dependency on function B. If no other functioncalls function B, then in 807 a module or file may be created containingboth function A and function B.

If in 806 it is determined that function B is called by function C, thenseparate modules or files may be created for function A and function B,respectively. Said another way, if function B may be legitimatelyincluded in multiple modules (or files), then function B may be givenits own module or file. It should be noted that in various embodiments,dependencies between modules may be stored either in the modulesthemselves or in some type of module dependency table or its equivalent.

Finally, in 812, a determination may be made as to whether there areadditional functions to analyze. If there are no more functions in thecallback system, then the method may terminate or exit, as shown.Otherwise, the method may continue, selecting the next function in thecallback system to analyze, as shown in 802, and described above.

Thus, if function A calls function B, and function B is only called byfunction A, then a module or file containing function A's definition mayalso contain function B's definition. Under this scenario, thedependency checker will know that function A and function B areinterrelated and part of the same file. If function A calls function B,and function B is also called by function C, then function A's module orfile will not contain function B in its definition file, and so functionB's definition may be included in a separate file (or module). And so,by using the method above, the functions of a callback system in agraphical program execution engine may be modularized to allow thedependency checker to find and retrieve only those modules or files thatare needed by the application, where the modules or files are organizedto minimize the number of unnecessary functions included in thegraphical program flatfile.

FIG. 9—Generation of the Graphical Program Flatfile

FIG. 9 graphically illustrates the process of generating a graphicalprogram flatfile 207 from graphical program 202 and the modular callbacksystem 206. As FIG. 9 shows, a dependency checker program or process mayanalyze the graphical program 202 with respect to the modular callbacksystem 206 to determine required modules 902. For example, in theembodiment shown, in the (extremely simple) graphical program 202,function K 722 is executed, then function C 706 (which calls function E710 implicitly) is executed. Finally function E 710 is executed(explicitly). Thus, as is well known in the art, the graphical programnot only indicates the functions called, but the sequence of execution,as well.

The dependency checker may thus may determine that module 2 764 andmodule 4 768 are required by the graphical program. This information maythen be used in conjunction with execution sequence information from thegraphical program 202 to generate the flatfile, as indicated in FIG. 10.Further details of the flat file are provided below with reference toFIGS. 10 and 11A-11C.

VI Object Files

In the process of generating the flatfile for an application program,one or more object files may be produced, e.g., via a utility such asVI2OBJ or its equivalent. The reasoning behind this approach is due tothe storage limitations of many embedded devices. For example, loadingan entire VI to the target device 110 may require more RAM than isavailable on the device, and execution of Vis directly from flash maynot be possible because there is not enough RAM memory to copy these VIsinto RAM and execute from there. It should be noted that as used herein,the term “program” may refer to the original source code of a program(e.g., the graphical diagram and underlying code, or text source code,such as C code), to object code generated from the source code, or toexecutable machine code generated from the source or object code.

However, because the callback system modules (generated from C/C++code), described above, must be loaded onto the target device 110, it isnatural to implement a common mechanism for loading VIs and modules.Thus, a VI2OBJ linker/loader may be developed based on the idea that VIscan be saved, not in their native format, but as object files, such thatan ordinary C linker may be used to process them—i.e. to transform theminto shared objects that can be loaded at runtime into the target device110. This approach may make generation of executables from VIs easy andstraightforward when space is limited. VI2OBJ or its equivalent is amechanism to transform a VI (ex: add_int.vi) into an object file (ex:add_int.o).

To describe the mechanism involved in transforming a VI to an objectfile, the general structure of a VI should be considered. Omittingirrelevant information, the six major components are:

1. Compiled code—executable binary code of a VI;

2. Data space—stores all the data that is required by the VI to run;

3. Data space type map—describes the data stored in the data space;

4. Connector panel—describes the inputs & outputs of a VI;

5. Front panel heap—hosts the controls, indicator & cosmetics etc.; and

6. Block diagram heap—hosts the nodes & wires that make up the blockdiagram.

Another important piece of information is the linkinfo, which describesconnections made from a VI to various entities, e.g., subVIs, externalfunctions etc.

Now, the above listed components may be reshaped into an object filebased on the following considerations:

1. The generated object file may be processed by an ordinary C linker(the VI may be linked to other support modules and eventually used togenerate the flatfile).

2. It may be desirable to use the original execution mechanism of VIs onthe target device 110.

3. The overhead induced by the new loading mechanism should beminimized.

4. Additional processing required after the VI is loaded by targetdevice 110, up to the point where it is ready to run, should beminimized.

5. The object file size should be minimized.

To minimize the object file size the front panel heap and the blockdiagram heap may be omitted from the VI, because they are not needed onthe target device 110 at run time, i.e., they are only used on the hostcomputer side at edit time. As is well known in the art, an object fileis substantially a file comprising of blocks of information (e.g., code,data, etc.), symbol information, and relocation information. In oneembodiment, the steps taken to create an object file from a VI mayinclude:

1. placing the compiled code resulting from the VI into the section codeof the object file, extracting the symbol information attached to the VIcode, and adding relocation information for local and external functioncalls.

2. creating a data section for the object file containing initializeddata, e.g., data space type map block of the VI, default data space,connector panel and VI InstrHandle structure (enabling some of theinitialization for a VI on the host side), etc. Additionally, symbolinformation may be added to facilitate retrieval and use of informationstored in this section.3. creating a .bss section for un-initialized data and storing relatedsymbol information there.4. extracting patch information from the linkinfo block and storing thisinfo in a data section (e.g., named linkdata). This information mayinclude a set of symbol and relocations entries. The data section may beused to store links from the VI to other subVIs or external modules.5. finally, calls may be generated for InitVI and UnInitVI functions(and stored in two special sections: .ctors and .dtors, of the objectfile). These functions may be responsible for VI initialization anddisposal on the target device side.

Performing the steps described above may generate an object file thatcontains all the information needed by a VI to run, and that alsoincludes symbol and relocation information used to connect this VI withother VIs or modules.

FIG. 10—Method for Generating the Graphical Program Flatfile

FIG. 10 is a high-level flowchart of one embodiment of a method forgenerating the graphical program flatfile 207, as illustrated in FIG. 9.As mentioned above, in various embodiments, one or more of the steps maybe performed in a different order than shown, or may be omitted.Additional steps may also be performed as desired.

As FIG. 10 shows, in 1002, a graphical program 202 may be analyzed withrespect to function dependencies to generate a list or collection ofrequired modules. In other words, a dependency checker residing on thehost computer system 102 may determine the functions used in thegraphical program, then select modules from the modularized callbacksystem 206 which contain those functions to generate required modules902.

After (or before or during) the required modules 902 are determined, thegraphical program 202 may be analyzed to determine an execution sequenceor order of the functions called by the program (or by other functionsin the program 202). In other words, the program flow for the graphicalprogram 202 may be determined.

Finally, the flatfile 207 may be generated based on the required modules902 and the execution sequence for the program. In one embodiment, theflatfile 207 may be generated by including the required modules 902 inthe flatfile 207 along with sequencing information and/or moduledependency information. An exemplary structure and format of thegenerated flatfile 207 is presented below with reference to FIGS.11A-11C.

In one embodiment, the flatfile 207 may be generated from an object fileand a symbol map of the target executable (the graphical program). As anexample, assume that the object file is named add_int.o (for adding twointegers) and the flatfile name, will be add_int.flat.

First, a symbol map (named mb.sym) may be generated from the graphicalprogram, e.g., by using a special tool, e.g., a symdump tool. The symbolmap contains all the global symbols of the graphical program along withthe sections where they belong, and their addresses relative to thebeginning of the section. Section names of the graphical program maythen be extracted (e.g., from mb.sym), and numbered, e.g., beginningwith one. Section names of add_int.o may then be extracted and numbered,e.g., beginning with 100. Thus, symbol lookup may be done at the time ofthe flatfile creation.

Then, symbols may be extracted from mb.sym and add_int.o. Relocationinformation may be extracted from add_int.o. Relocation information inan object file may include the address where the relocation is neededand the symbol name for the relocation. In one embodiment, therelocation information in a flatfile may comprise tuples (clusters,structures, etc.) of {[address where the relocation is needed (uInt32)],[the target section (uint16)], [the target address relative to the startof the start section]}. Further information regarding relocation isprovided below.

For every relocation in the add_int.o, the symbol name may be searchedfor in mb.sym and add_int.o, and, if the symbol is not found, then anerror message may be generated and the method terminated. If the symbolis found, the relocation may be written to the flatfile, i.e., toadd_int.flat.

Finally, each section's content may be written to the flatfile. In oneembodiment writes to the flatfile 207 may be made in accordance with theformats for relocation, etc., for a flatfile, described below.

It should be noted that in a preferred embodiment, unlike DLLs (DynamicLink Libraries), flatfiles are “targeted”. In other words, flatfiles aregenerally built to be loaded by a specified program. Thus, a crash orerror may occur if another program tries to load a flatfile that was notbuilt for it. Also, in one embodiment, the version of the symbol mapshould match the version of the graphical program. This versioncompliance may be facilitated by using a “build timestamp” in theapplication and in the mb.sym, so verification of the “version match” ispossible.

Relocation

Relocation refers to writing the code section of an application at acertain memory address and preparing the code for execution. Preparationincludes modification of the code according to a relocation table suchthat at execution time the code is able to access the variables andfunctions that it needs for its task. Examples of relocation arepresented below.

Relocating Code

A program, at compile time, is set to run at certain memory addresses,say Xtext for the code section and Xdata for the data section. However,when the program is dynamically load into the target device 110, it isvery possible that these addresses are already occupied, or may not evenexist on the target device 110. Therefore, the code and data sections ofthe program may be placed in different memory locations on the targetdevice, say Ytext and Ydata.

For example, if the program contains the following C instruction:

i=0;

and the address of variable i is (Xdata+100) (an offset of 100, forexample, with respect to Xdata)

After code compilation, the following assembly line of code may beproduced:

mov [Xdata+100], 0

meaning “move the value 0 at address Xdata+100”.

Now assuming that the code section is transferred to the target device110, and Xdata becomes Ydata, the target device address of variable i isnow (Ydata+100). The process that corrects the instruction

mov [Xd+100], 0

to

mov [Yd+100], 0

is called relocation. The relocation process uses the Relocation Tableto determine the address in the code section for the instruction

(mov [Xd+100], 0).

and how this instruction needs to be changed.

In one embodiment, one or more of the following constraints may apply tothe target device:

1. target flash should be large enough to be able to store the flatfilecode, constructor, destructor and read-only sections.

2. target RAM should be large enough to store the flatfile data sectionand also the largest relocation table.

Relocating Data

The following is an example of relocation in the Data Section (.data).Assume that the program includes the following code sequence:

int i;

int *j=&i;

i is an un-initialized variable, so it may be stored in theun-initialized data (.bss) section. j is a variable that will containthe address of variable i, so after being initialized it may be storedin the data section. Because j will eventually have to contain theaddress of i, a relocation may be necessary in the data section to theaddress of j.

FIGS. 11A-11C—Structure and Deployment of the Graphical Program Flatfile

FIGS. 11A-11C illustrate the structure and deployment of the graphicalprogram flatfile 207, according to one embodiment. FIG. 11A illustratesone embodiment of the contents of the modules used to build the flatfile207. FIG. 11B illustrates the structure of the flatfile 207, accordingto one embodiment. Finally, FIG. 11C illustrates the deployment of theminimal graphical program execution system 205 and the constructedcombined program 202A.

As FIG. 11A shows, in one embodiment, a module 1100, as referred toabove with reference to FIGS. 6 and 7, may include three components: asections component 1102, a symbols component 1104, and a relocationtable 1106. In one embodiment, the module is a piece of C or C++ codecontained in one or more C or C++ files. Every module may be compiledinto an object file which contains the executable code and the datagenerated by the compiler for a specific module, along with symbolic andrelocation information for that module, and other information, such asdebug info, comments, etc.

The sections component 1102 may include six sections which representvarious aspects of the module 1100, as shown in FIG. 11A. Morespecifically, the sections may include a code section 1112 which is theprogram code for the module, a data section 1113, a constructor 1114 forthe module, a destructor 1115 for the module, a un-initialized datasection 1116, and a data read-only section 1117 (i.e., for constants). Asection may comprise a range of addresses with no gaps; all data inthose addresses may be treated the same for some particular purpose. Thesymbols component 1104 includes the variables and function names for themodule. A symbol is a name associated with a given address in a givensection. The symbolic and relocation information from the object file ofthe graphical program can be used to determine the dependency relationbetween modules.

One characteristic of the object file is that it can be relocated,meaning that with appropriate processing, object file sections can bystored and executed at any memory address. As described in detail above,relocation is the process that makes an object file able to run at agiven address. The information (table) that the relocation process usesis referred to as relocation information (or the relocation table) andis preferably included in the flatfile 207. Thus, the relocation table1106, also referred to as an address table, provides the relativeaddresses for the symbols (variables and functions) with respect to theprogram on the host computer 102. This relocation information may beused by the target device to construct the combined program 202A, addingan address offset to the addresses in the relocation table 1106 togenerate correct locations for the symbols in the context of the targetdevice 110.

Thus, once the graphical program has been compiled to an object file,the object file may contain sections such as:

SectionA

Relocation information for SectionA

Symbol information for SectionA

Debug information for SectionA

SectionB

Relocation information for SectionB

Symbol information for SectionB

Debug information for SectionB

SectionC

Relocation information for SectionC

Symbol information for SectionC

Debug information for SectionC

etc. in no specific section order.

The information in each module 1100 may be included in the flatfile 207,as shown in FIG. 11B.

As FIG. 11B shows, the flatfile 207 may include an initial segment 1120(reading left to right) which includes information regarding the moduleinformation in the flatfile 207. In one embodiment, this section may beabout 100 bytes in size, and may include such information as the numberof sections in the flatfile, the size of each section in bytes, and thetype of each section, e.g., code 1112, data 1113, etc.

After this initial section information segment 1120, one or more modulesegments, referred to as flatobjects, may be included, as FIG. 11Bshows. In one embodiment, each module segment may include the moduleinformation shown in FIG. 11A, i.e., each module segment may includerelocation table 1106 and sections 1102 for a respective module 1100.

FIG. 11C illustrates the deployment of the minimal execution system 205and the combined program 202A on the target device 110. As FIG. 11Cshows, the minimal execution system 205 may be divided between RAM 1130and flash memory 1140 on the target embedded device 110. In theembodiment shown, the RAM 1130 is of size 128 k and stores data andun-initialized data for the minimal execution system 205. As FIG. 11Calso shows, in this embodiment, 128 k of the flash memory 1142 is usedto store the real-time OS (e.g., eCos) and the code and read-only datafor the minimal execution system 205. The remainder of the flash memory1140 may be used to store the combined program 202A which may beconstructed based on the flatfile 207. It should be noted that the RAM1130 may also be used to store data during execution of the combinedprogram 202A.

Thus, the flatfile 207 may include module information for functions ofthe graphical program 202 and for functions included from the modularcallback system. In other words, the functions (with variables) for thegraphical program 202 have been combined with the execution systemfunctions required to execute those graphical program functions. Thismodule information also includes relative address information forre-locating the functions in the memory space of the target device 110.The flatfile 207 may be transmitted to the target device 110 where aflatfile loader may execute to receive the flatfile 207 and constructthe combined program 202A. Further details of the process ofconstructing the combined program 202A from the flatfile are providedbelow with reference to FIG. 12.

Detailed Structure of Flatfile

The following describes one embodiment of flatfile structure or formatin more detail. It should be noted that the following format isexemplary and it only intended for illustration purposes, i.e., is notintended to limit the structure or format of the flatfile to anyparticular design.

Flatfile: sec_nr (int32) Number of sections; sec_desc[sec_nr] - An arrayof sec_nr section descriptors. See the format of sec_desc below;sec_content[sec_nr] - An array of sec_nr with section contents. See theformat of sec_content below; sec_desc: sec_size (uInt32) - the size ofthe section data; sec_type (uInt32) - type of the section. A combinationof FO_SEC_READONLY, FO_SEC_HAS_CONTENT, FO_SEC_IS_CTOR_TABLE,FO_SEC_IS_DTOR_TABLE; number (uInt32) - a unique number for everysection; sec_content: rel_desc - relocations for this section. Seebellow for rel_desc structure; section_data - the raw data of thesection; rel_desc: rel_nr (uInt32) - number of relocation in thisrelocation descriptor; rel_data[rel_nr] - an array of rel_nr relocationsdata - See bellow for the rel_data structure; rel_data: addr (uInt32) -the relocation address, relative to current section start; target_sec(uInt16) - the section where the relocation should point; target_addr(uInt32) - the address relative to target section address where therelocation should point; rel_type (uInt16) - the type of the relocation.FIG. 12—Method For Deploying and Executing a Graphical Program

FIG. 12 flowcharts one embodiment of a method for creating, deploying,and executing a graphical program on an embedded device. Morespecifically, a method is described for creation and deployment ofprograms on the target device 110. It is noted that in variousembodiments, some of the steps may be performed in a different orderthan shown, or may be omitted. Additional steps may also be performed.As shown, this method may operate as follows.

In one embodiment, the user first may create a program that is operableto execute within the target embedded device, as indicated in 1202. Increating the program, the user may be aware of the one or more sensordevices 120 which will be acquiring data in the system. The user mayinclude code in the program which is operable to execute on the targetdevice, and which operates to provide instructions to one or more ofsensor devices 120 to direct sensor devices 120 to acquire data atcertain times or based on certain detected events. In one embodiment,the user may create a graphical program on computer system 102. As notedabove, a graphical program may comprise graphical code, i.e., two ormore interconnected nodes or icons which visually represent operation ofthe program. In creating the program, the user may place icons withinthe graphical program representing each of the respective sensor devices120 that are being used. The user may also include graphical code in theprogram which operates to provide instructions to the respective sensordevice icons, i.e., by connecting other graphical nodes to the sensordevice icons in the graphical program. Thus, the graphical program maybe created or assembled by the user arranging on a display a pluralityof nodes or icons and then interconnecting the nodes to create thegraphical program. In response to the user assembling the graphicalprogram, data structures may be created and stored which represent thegraphical program. The nodes may be interconnected in one or more of adata flow, control flow, or execution flow format. The graphical programmay thus comprise a plurality of interconnected nodes or icons whichvisually indicates the functionality of the program. As noted above, thegraphical program may comprise a block diagram and may also optionallyinclude a user interface portion or front panel portion. Where thegraphical program includes a user interface portion, the user mayassemble the user interface on the display. As one example, the user mayuse the LabVIEW graphical programming development environment to createthe graphical program.

As described below, the block diagram may be intended to execute on thetarget device 110. The user interface code may remain on the hostcomputer 102 and may execute on the host computer 102 to present theuser interface on the host computer 102 during execution of the blockdiagram on the target device 110. The user may interact with the userinterface presented on the host computer 102 to provide input to and/orview output from the block diagram executing on the target device 110.

In an alternate embodiment, the graphical program may be created in step1202 by the user creating or specifying a prototype, followed byautomatic or programmatic creation of the graphical program from theprototype. This functionality is described in U.S. patent applicationSer. No. 09/587,6102 titled “System and Method for AutomaticallyGenerating a Graphical Program to Perform an Image ProcessingAlgorithm”, which is hereby incorporated by reference in its entirety asthough fully and completely set forth herein. The graphical program maybe created in other manners, either by the user or programmatically, asdesired. The graphical program may implement a measurement function thatis desired to be performed by the instrument. For example, in anembodiment where the instrument is an image acquisition device (e.g., asmart camera), the graphical program may implement an image processingfunction.

Once the program has been completed, then in step 1204, the graphicalprogram flatfile may be generated, as described above with reference toFIG. 10. One embodiment of this is described in detail below in thesection Example Process. In one embodiment, where the graphical programincludes a block diagram and a user interface, only the block diagramportion may be used in generating the flatfile. The user interface mayremain as code that executes on the host computer 102.

Then, in 1206, the flatfile may be transmitted to the target device 110,e.g., over a network (or other transmission means). In other words, theuser may cause the computer system to send the flatfile 207 over thenetwork 104 (or other communication medium) to the target device 110.

The target device 110 may thus receive the flatfile 207, and aloader/linker program on the target device 110 may construct thecombined program 202A based on the received flatfile 207, as indicatedin 1208. Further details of one embodiment of this process are providedbelow in the Dynamic Linking section and the Example Process section.

Finally, as shown in 1210, the target device 110, e.g., the minimalexecution system 205 on the target device 110, may execute the combinedprogram 202A.

In one embodiment, the target device 110 may send output data (e.g.,acquired data or execution results) to the host computer 102. The datamay be transmitted to the computer 102 over the network 104, e.g.,through wired or wireless means. The target device 110 may send theoutput data through one or more intermediate devices, such as a hubdevice 108. The host computer system 102 may display the received datain a GUI, and/or may otherwise process the received data to generate acertain result. In one embodiment, the user constructs a GUI or frontpanel as part of the process of creating the graphical program, and thisGUI code is executed on the computer system 102 to present the GUI onthe display of the computer system 102.

In one embodiment, in executing the program received from the computersystem, the target device 110 may be directed by the program to providecertain commands to respective ones of sensor devices 120 to cause thesensor devices to acquire data and provide this acquired data to thetarget device. Examples of the types of commands that may be implementedby sensor devices 120 include, but are not limited to, single/multiplepoint read, writes (e.g., for configuration) start, and stop, amongothers. In one embodiment, prior to sending the program to the targetdevice 110, the minimal execution system 205 may be deployed to thetarget device 110. In another embodiment, the target device 110 mayalready have the execution system 205 installed.

Thus, the target device 110 executes the program received from thecomputer system 102, e.g., via the execution system 205. In oneembodiment, the target device 110 may execute the program upon receptionof the program from the host computer 102. In another embodiment, afterthe program has been transferred to the target device 110, the user maysend a command to the target device 110 over the network 104 invokingexecution of the program by the target device 110. In an exemplaryembodiment, the execution of the program results in some data beingacquired or generated. These data may then be sent (e.g., over thenetwork 104 or other communication medium) to the host computer system102, e.g., for display and/or analysis. In other embodiments, theacquired data may be sent to other systems. For example, in oneembodiment, the target device 110 may use web server program 604 topublish the acquired data to a website, where a system with a webbrowser may then access the data. In another embodiment, the targetdevice may send the data to one or more other systems coupled to thenetwork 104 (e.g., the Internet). Thus, the target device may send theacquired data to any networked devices, as desired.

Dynamic Linking of Flatfile to the Target:

As described above, in a preferred embodiment, the flatfile 207 maycomprise a sequence of sections and relocation tables. The sections canbe code, data, constructors, etc.

When the flatfile is constructed on the host computer, the code in itssections is relative, meaning that the instructions described in thiscode do not have real target addresses for the variables but rather somegeneric addresses, e.g., with respect to the beginning of the program.

For example, the program may include an instruction:

Move to variable I at address 10, the value 0 (I=0)

Now, as mentioned above in 1206, the flatfile may be transmitted to thetarget device, say, for example, in chunks of 4 kbytes. The very firsttransfer contains the initial 100 bytes 1120 that give informationregarding the total number of sections, their type, and size, and therelocation tables that come with them, as described above with referenceto FIG. 11B. Based on this information memory on the target device 110may be reserved to accommodate these sections.

Now, the code:

Move to variable I at address 10, the value 0 (I=0)

arrives at the Target. Based on the relocation table, it may bedetermined that the real target address of variable I is not 10 butrather 500 offset+10=510 because in the datav section of the target RAMall program variables are addressed with relative to address 500.So at this time, when the flatfile is moved into the target device 110the call toMove to variable I at address 510, the value 0 (I=0)has been corrected. In other words, the offset (500) has been added tothe address. In one embodiment, the call may not be executedimmediately, but rather may be stored or written in a code section ofthe flash location 1140.

In one embodiment, after the entire flatfile has been transmitted to thetarget and processed, the constructed combined program may be executed.In another embodiment, the execution of the constructed combined programmay occur as the flatfile is streamed to the target device 110, asdescribed below.

Example Process

The following is a simple example of one embodiment of the abovedescribed processes. In this example, the user creates a VI on the hostcomputer 102, named Delay.vi, and wishes to run this VI on the targetdevice 110.

On the host computer 102, the VI is transformed into an object filenamed Delay.o. The modules required for running the VI are determined bya dependency checker executing on the host computer 102, producing thefollowing list (for example):

uClibc/memmove.o (from directory uClibc take file memmove.o)

cookie/mbCookie.o

occur/mbOccur.o

uClibc/memcpy.o

So at this point, the application VIs are converted into object files,and the required modules (that are also compiled into object files atthis point) from the modular callback system 206 are determined. Then,all the object files pertaining to the application (using an ordinary Clinker) are lined into a single object file which becomes the“application object file”. In other words, the following object filesmay be merged together:

Delay.o

uClibc/memmove.o

cookie/mbCookie.o

occur/mbOccur.o

uClibc/memcpy.o

thereby creating one single “application object file named” exampleVI.o.It is noted that in this example, the “application object file” may nowbe organized thusly:

All code sections (of type .text) with related relocation, symbol anddebug information from Delay.o, memmove.o, mbCookie.o, mbOccur.o, andmemcpy.o are assembled into one big code section (of type .text) withrelated relocation, symbol and debug information in the resultingexampleVI.o.

All data sections (of type .data) with related relocation, symbol anddebug information from Delay.o, memmove.o, mbCookie.o, mbOccur.o, andmemcpy.o are assembled together into one big data section (of type.data) with related relocation, symbol and debug information in theresulting exampleVI.o

All constructor sections (of type .ctors) with related relocation,symbol and debug information from Delay.o, memmove.o, mbCookie.o,mbOccur.o, and memcpy.o are assembled together into one big constructorsection (of type .ctors) with related relocation, symbol and debuginformation in the resulting exampleVI.o.

All code destructor (of type .dtors) with related relocation, symbol anddebug information from Delay.o, memmove.o, mbCookie.o, mbOccur.o, andmemcpy.o are assembled together into one big destructor section (of type.dtors) with related relocation, symbol and debug information in theresulting exampleVI.o.

All read_only sections (of type .rodata) with related relocation, symboland debug information from Delay.o, memmove.o, mbCookie.o, mbOccur.o,and memcpy.o are assembled together into one big read_only section (oftype .rodata) with related relocation, symbol and debug information inthe resulting exampleVI.o.

All un_initialized data sections (of type .bss) with related relocation,symbol and debug information from Delay.o, memmove.o, mbCookie.o,mbOccur.o, and memcpy.o are assembled together into one bigun_initialized data section (of type .bss) with related relocation,symbol and debug information in the resulting exampleVI.o.

At this point, exampleVI.o contains:

Code section

Relocation info for Code section

Symbol info for Code section

Debug info for Code section

Data section

Relocation info for Data section

Symbol info for Data section

Debug info for Data section

Constructor section

Relocation info for Constructor section

Symbol info for Constructor section

Debug info for Constructor section

Destructor section

Relocation info for Destructor section

Symbol info for Destructor section

Debug info for Destructor section

Read_Only section

Relocation info for Read_Only section

Symbol info for Read_Only section

Debug info for Read_Only section

(in no specific order).

However, a typical object file has a very complicated internal structureand thus may not be suitable for sequential processing (on the targetdevice 110). Therefore, in order to be able to load, dynamically link,and sequentially process an object file on the target device 110, theobject file may be processed into a different format called theflatfile, described above in detail.

The flatfile is an object file that has a much simpler structure than aregular object file, and therefore it may be processed “on the fly” orsequentially on the target device 110. In one embodiment, a utility,referred to as obj2flat, that transforms an object file into a flatfile,may be developed and used. Therefore, by running the obj2flat utility onexampleVI.o a single flatfile file named exampleVI.flat may begenerated.

In one embodiment, the exampleVI.flat file may include:

Section table Relocation Table for Code Section Code section RelocationTable for Data Section Data section Relocation Table for ConstructorSection Constructor section Relocation Table for Destructor SectionDestructor section Relocation Table for Un-initialized Data SectionUn-initialized Data section Relocation Table for Read_Only SectionRead_Only section Note1: for flatfiles the order of information is veryimportant. Note2: in converting exampleVI.o to exampleVI.flat, debuginformation may be omitted, while the symbol information may be used tocreate the relocation tables.

The section table gives information for every section regarding thenumber of sections, the size of each section in bytes, and the type ofeach section, as described above. The section table may be required topre-allocate the memory for the sections. The idea is that in therelocation process, all section addresses must be known, and soallocation of memory for sections is preferably the first step performedon the target device 110.

Once the flatfile has been generated, exampleVI.flat may be transferredto the target device. In one embodiment, the target device has a networkbuffer in RAM that is 4K wide (although in other embodiment, the networkbuffer may be set to any size desired). Based on the size of thisbuffer, transfers of information from exampleVI.flat to target deviceRAM may be made in chunks of 4K.

The very first 4K piece of exampleVI.flat arrives via the network intoRAM on the target device 110. This 4K of data contains the SectionTable, Relocation Table for the Code Section, and some Code Section. Thedynamic linker (or loader) that resides in Flash memory of the targetdevice 110 may be a state machine with two run modes: read information,and process information.

Once the very first 4K transfer arrives in target device RAM, thedynamic linker enters read mode and starts reading the Section Table.When the Section Table is completely read, the dynamic linker entersprocessing mode and stores the Section Table in another location intarget RAM, then executes the Flash memory allocations for the sectionsdescribed in the Section Table. After finishing the allocations, thedynamic linker enters read mode, and reads the Relocation Table for CodeSection. When the Relocation Table for Code Section is completely read,the dynamic linker enters processing mode and stores the RelocationTable for Code Section into target RAM at a different location than the4K network buffer and the Section Table locations. Then it uses theinformation from the Relocation Table for Code Section to process thecontent of the Code Section that is already in the target RAM. When theentire portion of the Code Section currently in RAM has been processed,a new 4K transfer from exampleVI.flat into the network buffer takesplace, overwriting the previous 4K information. Note that at this time,the Section Table and Relocation Table for Code Section have been savedinto other target RAM locations, so the dynamic linker can proceed withprocessing of the Code Section by using information from the RelocationTable for Code Section. After the Code Section is completely relocated,the Relocation Table for Code Section may not be not needed anymore.

Next, the Relocation Table for Data Section is read into the 4K networkbuffer. When the Relocation Table for Data Section Code is completelyread, the dynamic linker enters processing mode and stores theRelocation Table for Data Section into target RAM, overwriting theRelocation Table for Code Section. Then the dynamic linker uses theinformation from the Relocation Table for Data Section to process thecontent of the Data Section that is already in target RAM. When theentire portion of Data Section in RAM has been processed, a new 4Ktransfer from exampleVI.flat into the network buffer takes place,thereby overwriting the previous 4K information. Note that at this time,the Relocation Table for Data Section has been saved into target RAM, sothe dynamic linker can proceed with processing of the Data Section byusing information from the Relocation Table for Data Section.

These 4K transfers and dynamic linker read/process cycles may continueuntil the entire exampleVI.flat file has been transferred to the targetdevice 110 and the combined program 202A has been constructed (in theflash program space 1144). After the entire exampleVI.flat file iscompletely transferred to the target device, the Section Table will notbe not needed anymore, and so may be deleted, and the constructedcombined program 202A may be run.

Thus, in summary, in one embodiment of the invention, the program thatis created on the computer system 102 may require use of programexecution system 205 to execute the program. For example, in oneembodiment, the program is a graphical program and requires graphicalprogram execution system 205 to execute the program. Due to the smallfootprint of target device 110, in one embodiment, the program executionsystem is configured in such a way so as to only transmit the minimumamount of a program execution system (i.e., a portion of the modularcallback system 206) actually required by the program that is beingexecuted. Thus, in one embodiment, the program execution system ispartitioned into a (minimal) base execution system, and a plurality ofcomponents for presenting different functionality that can be performedby a program. The base portion of the program execution system is onlycapable of executing the very simplest commands. This minimal engine maycomprise the smallest set of commands which allows the other componentsto be executed.

In one embodiment, when the program is developed by the user, a softwareprogram executing on the computer may operate to analyze the program todetermine the functionality contained in the program. Once thefunctionality of the program has been identified, the program uses thefunctionality to determine which of the respective components of theprogram execution system are actually required by the program. In oneembodiment, the method determines the functionality of the program, anduses the functionality to index into a data structure or look-up tableto determine which program execution system components will be requiredto execute this program. When the program is then transmitted ordeployed to target device 110, the computer system may operate to onlyprovide the program execution system base portion and the respectivecomponents that are actually required to execute the program. Thus, thesmaller amount of execution system code may be transmitted to the targetdevice. This allows a smaller footprint for one or more of the targetdevices and/or the sensor devices. In other words, target device 110 mayinclude a smaller processor and/or a smaller memory medium since a fullprogram execution system is not required to be transmitted.

In one embodiment, after the software program analyzes the program todetermine the functionality contained in the program, an executionsystem analysis program may determine which execution system componentsare required for execution of the program. A deployment program may thenassemble the required components of the execution system and theprogram, for example, by interspersing the required execution systemcomponents and the program together according to the order of executionof the program. These interspersed program execution system componentsand program may then be assembled into a file (i.e., the flatfile 207),and respective portions of the file transmitted to the target device 110for execution.

In one embodiment, the flatfile 207 may be received by the target device110 and used to construct a combined program 202A including executablecode from the program and executable code from the required executionsystem. This combined program 202A may then be executed by the embeddeddevice 110. The combined program may also be stored in non-volatilememory of the embedded device for subsequent execution.

Streaming Execution

In one embodiment, successive portions of the file may be streamed tothe target device 110 and/or sensor device 120 for dynamic execution. Inother words, the target device may execute the program as it is streamedto the device. For example, the sensor device 120 may receive a firstportion of the file comprising a first portion of a program to beexecuted at a first portion of the execution system components that areused for executing this first portion of the program. After this firstportion of the program has been executed along with the first portion ofthe execution system components, the first portion of the program may beflushed or removed from the memory of the sensor device. In a similarmanner, the execution system components that are no longer required maybe also removed from the memory. However, execution system componentsthat may be required by other portions of the program to be executed maybe retained in the memory for execution. As discussed above, in oneembodiment, the deployment program determines which execution systemcomponents may be required for a plurality of different portions of theprogram, and includes a variable or data structure or other indicationwith the execution system component to indicate that this componentshould not be flushed immediately after it has been executed, or othersshould be retained by target device 110 for execution with another partof the program.

After the first portion of each of the program execution components andthe program has been executed, computer system 102 and/or target device110 may then provide a second portion of the program interspersed withthe second portion of the execution system components. The secondportion of the file may be provided by the computer system to targetdevice 110. Operation then proceeds as above. Thus, for example,computer system 102 may operate to provide respective portions of thedeployment file to target device 110 for execution on an as neededbasis, based on the memory availability or memory capacity of targetdevice 110. Target device 110 may receive the program that it issupposed to execute along with the execution system components used bythat portion of the program, execute the program under direction of theexecution system components, and then receive further portions of thedeployment file, and so forth. Thus, computer system 102 may essentiallyprovide a stream of the program and its corresponding execution systemcomponents to the target device according to the order of execution ofthe program.

In an example application of the present system, the computer system102, the target device 110, and/or the hub device 108, may operate toexecute a radio server program which is operable to discover remote orwireless data acquisition devices that enter into and exit from thewireless communication space that is within the range of the targetdevice. Thus, periodically, the radio server executing on the targetdevice may send out a wireless communication signal to query thepresence of respective data acquisition devices 120 that are within thewireless communication range of the computer system 102, target device110, or hub 108. Any present data acquisition devices may respond to thequeries to indicate its respective presence. The queries may beperformed periodically, e.g., once permitted, once per hour, once perday, or at greater or lesser time frame granularities. For furtherinformation regarding wireless execution of the graphical program,please see U.S. Provisional patent application Ser. No. 60/393,528,titled “Wireless Deployment/Distributed Execution of Graphical Programsto Smart Sensors”, filed Jul. 3, 2002, which was incorporated byreference above.

In another embodiment of the present invention, the target device 110may include a programmable hardware element, such as an FPGA, inaddition to, or instead of, a processor. For example, in an embodimentwhere the target device includes both a processor/memory and an FPGA,the graphical program may be compiled to a hardware configuration fileon the host computer system 102, where the hardware configuration fileis targeted at the FPGA on the target device 110. The host computer maytransmit the hardware configuration file to the target device 110, whereit may be stored, e.g., in a memory medium of the target device. Theprocessor on the target device may then deploy the hardwareconfiguration file onto the FPGA, after which the configured FPGA mayexecute to perform the desired function or operation.

In another embodiment, the target device may include two (or more)FPGAs. The host may stream the compiled hardware configuration file tothe target device in portions which are each suitable for deployment andexecution by respective ones of the FPGAs. Execution of the program mayproceed in “ping-pong” fashion among the two or more FPGAs. For example,once a first portion of the hardware configuration file is received anddeployed on a first FPGA, the configured first FPGA may execute, therebyperforming a function encoded in the first portion of the hardwareconfiguration file. While the first FPGA is executing the first portionof the hardware configuration file, a second portion of the hardwareconfiguration file may be received and stored in the memory medium ofthe target device. The processor may then deploy this second portion ofthe hardware configuration program to a second FPGA on the target device110. Once the second portion is deployed, the second FPGA may beginexecution. In one embodiment, once the second portion is deployed to thesecond FPGA and the second FPGA begins execution, execution of the firstFPGA may be halted, and a third portion of the hardware configurationprogram may be received, stored in memory, and deployed onto the firstFPGA (now inactive). Thus, the FPGAs may be dynamically configured in analternating manner. Of course, this approach may be extended to morethan two FPGAs, where more sophisticated techniques may be applied todetermine which FPGA to configure with each successive portion of thehardware configuration program, e.g., round robin, longest inactive,size-based, etc.

It should be noted that additional material regarding variousembodiments of the invention are included in FIGS. 13 through 46.

Although the embodiments above have been described in considerabledetail, numerous variations and modifications will become apparent tothose skilled in the art once the above disclosure is fully appreciated.It is intended that the following claims be interpreted to embrace allsuch variations and modifications.

1. A method for receiving and executing a program, the methodcomprising: storing a linker/loader program; receiving a first part of afile from a remote device, wherein the file comprises a plurality ofcomponents of a program execution system and a program, wherein theplurality of components are operable to execute the program; storing thefirst part of the file; executing the linker/loader program to create afirst portion of a combined program from the first part of the file;storing the first portion of the combined program; deleting the firstpart of the file; receiving a second part of the file from the remotedevice; storing the second part of the file; executing the linker/loaderprogram to create a second portion of the combined program from thesecond part of the file; storing the second portion of the combinedprogram; deleting the second part of the file; and executing the firstportion and the second portion of the combined program to execute theplurality of components to execute the program.
 2. The method of claim1, wherein the program comprises a graphical program, comprising a blockdiagram portion and a user interface portion; wherein said receiving theprogram from the remote device comprises receiving the block diagramportion of the program from the remote device; and wherein, duringexecution of the program, the block diagram executes using the programexecution system and the graphical user interface is displayed on adisplay of the remote device.
 3. The method of claim 1, wherein theprogram comprises a graphical program; and wherein the graphical programcomprises a plurality of interconnected nodes that visually indicatefunctionality of the graphical program.
 4. The method of claim 1,wherein the combined program comprises the plurality of components ofthe program execution system and the program.
 5. The method of claim 1,further comprising: wherein the plurality of components are selected outof a larger plurality of program execution components byprogrammatically analyzing the program to determine required componentsfor execution of the program.
 6. The method of claim 1, wherein theplurality of components are determined based on functionality present inthe program.
 7. The method of claim 1, wherein the file comprises a flatfile, wherein the file is created by combining the plurality ofcomponents and the program into the file.
 8. The method of claim 7,wherein said combining comprises interspersing the plurality ofcomponents with the program according to an execution order of theprogram; and wherein the first and the second parts of the file arearranged according to the execution order of the program.
 9. The methodof claim 1, wherein the program execution system comprises one or moreof: a minimal execution engine; or a network manager.
 10. The method ofclaim 1, wherein said executing the first portion and the second portionof the combined program comprises executing each of the first and thesecond portions of the combined program after said storing eachrespective portion of the combined program.
 11. A computer-implementedmethod for creating and executing a program, the method comprising:generating a file based on a program and one or more execution modules,wherein the program is operable to execute on an embedded device,wherein the one or more execution modules are usable to execute theprogram, wherein the one or more execution modules comprise a minimalexecution system; transmitting the file to the embedded device, whereinthe file is transmitted in two or more parts; the embedded devicereceiving a first of the two or more parts of the file; the embeddeddevice constructing a combined program based on the first of the two ormore parts of the file, wherein the combined program includes programcode from the program and execution module code for executing theprogram code; the embedded device deleting the first part of the file;the embedded device receiving a second of the two or more parts of thefile; the embedded device constructing the combined program based on thesecond part of the file; and the embedded device executing the programusing the minimal program execution system.
 12. The method of claim 11,further comprising: the embedded device deleting the second of the twoor more parts of the file.
 13. The method of claim 11, furthercomprising: programmatically analyzing the program to determine requiredexecution modules for execution of the program; and selecting therequired execution modules in response to programmatically analyzing,wherein the required execution modules comprise the one or moreexecution modules.
 14. The method of claim 11, wherein said generatingthe file comprises interspersing the execution modules with the programaccording to an execution order of the program; and wherein the firstand the second parts of the file are arranged according to the executionorder of the program.
 15. The method of claim 11, wherein the executionmodule code includes code from the one or more execution modules.
 16. Amethod for receiving and executing a program, the method comprising:receiving a first part of a file, wherein the file comprises a pluralityof components of a program execution system and a program; storing thefirst part of the file in a memory; linking the first part of the fileinto a combined program; deleting the first part of the file from thememory; receiving a second part of the file; storing the second part ofthe file in the memory; linking the second part of the file into thecombined program; deleting the second part of the file from the memory;executing the combined program to execute the plurality of components toexecute the program.
 17. The method of claim 16, wherein the pluralityof components is required for execution of the program; and wherein theplurality of components is selected out of a larger plurality of programexecution components by programmatically analyzing the program todetermine required components for execution of the program.
 18. Themethod of claim 16, wherein the file comprises a flat file, wherein thefile is created by combining the plurality of components and the programinto the file.
 19. A method for receiving and executing a program, themethod comprising: receiving a first part of a file from a remotedevice, wherein the file comprises a plurality of components of aprogram execution system and a program; storing the first part of thefile in a first memory; creating a first portion of a combined programfrom the first part of the file; storing the first portion of thecombined program in a second memory; deleting the first part of the filefrom the first memory; receiving a second part of the file from theremote device; storing the second part of the file in the first memory;creating a second portion of the combined program from the second partof the file; storing the second portion of the combined program in thesecond memory; deleting the second part of the file from the secondmemory; and executing the first portion and the second portion of thecombined program to execute the plurality of components to execute theprogram.
 20. The method of claim 19, wherein the plurality of componentsis required for execution of the program; and wherein the plurality ofcomponents is selected out of a larger plurality of components of theprogram execution system by programmatically analyzing the program todetermine required components for execution of the program.
 21. Themethod of claim 19, wherein said executing the first portion and thesecond portion of the combined program comprises executing each of thefirst and the second portions of the combined program after said storingeach respective portion of the combined program.
 22. A method forreceiving and executing a program, the method comprising: storing alinker/loader program; receiving a first part of a file from a remotedevice, wherein the file comprises a plurality of components of aprogram execution system and a program, wherein the plurality ofcomponents are operable to execute the program; storing the first partof the file; executing the linker/loader program to create a firstportion of a combined program from the first part of the file; executingthe first portion of the combined program to execute one or more of theplurality of components to execute the program; deleting the first partof the file; receiving a second part of the file from the remote device;storing the second part of the file; executing the linker/loader programto create a second portion of the combined program from the second partof the file; and executing the second portion of the combined program toexecute one or more of the plurality of components to execute theprogram.
 23. The method of claim 22, wherein the file comprises a flatfile, wherein the file is created by combining the plurality ofcomponents and the program into the file.
 24. The method of claim 23,wherein said combining comprises interspersing the plurality ofcomponents with the program according to an execution order of theprogram; and wherein the first and the second parts of the file arearranged according to the execution order of the program.
 25. The methodof claim 22, further comprising: deleting the second part of the file.